1. Field of the Invention
The present invention relates to a seat slide rail with a seat lifter by means of which the seat can move up and down, and specifically to a lifter mounting structure that is optimally applied for a seat lifter mounted on an automobile seat slide rail unit, which consists of an upper slidable guide rail facing the bottom of the seat and a lower stationary guide rail rigidly mounted on the floor panel of the vehicle body, the upper and lower guide rails slidably fitted to each other so that the position of the seat relative to the floor is adjusted frontwards and backwards.
2. Description of the Prior Art
Recently, there have been proposed and developed various automobile seat slides equipped with a seat lifter. For instance, the conventional seat slide with the seat lifter has a lifter mounting structure as shown in FIG. 4. With regard to one seat slide rail unit 3, two seat lifters or seat lifting mechanisms 4 are placed at front and back ends of the seat slide rail unit 3, which has an upper slidable guide rail 2 facing the bottom frame 5 of the seat and a substantially C-shaped lower stationary guide rail 1 rigidly mounted on the vehicle body. In general, four seat lifters are placed at the respective front-left, front-right, rear-left and rear-right positions on the upper slidable guide rails, since two seat slide rail units are traditionally used for slidably supporting the seat. As seen in FIG. 4, the seat lifter 4 is generally fixed onto the upper surface of the upper slidable guide rail 2. As appreciated from the lifter mounting structure shown in FIG. 4, since the lifter 4 is simply put on the upper surface of the upper guide rail 2, the conventional structure requires an undesirably great amount of space enough to mount the lifter on the guide rail 2 in a vertical direction of the seat. As a result, the initial set-position of the seat is comparatively high. To avoid this, another lifter mounting structure has been disclosed in Japanese Patent Provisional Publication (Tokkai Heisei) No. 6-107055, which is assigned by the same assignee as the present application. In the Japanese Patent Provisional Publication No. 6-107055, in order to minimize the lifter mounting space, each seat support link constructing an essential part of the seat lifter is arranged to cover a substantially upper half of the upper slidable guide rail so that the lower portion of the seat support link and the upper portion of the slidable guide rail are overlapped with each other. However, the conventional lifter mounting structure disclosed in the above-noted Japanese Patent Provisional Publication suffers from the drawback in that the positioning of the respective seat support link is troublesome when assembling each seat support link on the associated upper slidable guide rail. Thus, it is desirable to enhance an efficiency of assembling the seat lifter on the upper guide rail.